EWOD (Electro Wetting on Dielectric) refers to the technology that the voltage applied between liquid and a solid electrode is adjusted to vary the surface tension of the liquid on the surface of the solid electrode so as to change the contact angle between them. In recent years, the droplet driving and controlling technology based on EWOD has drawn extensive attention and been applied in the flat-panel display field.
Currently, the EWOD display technology could mainly be classified into reflective type and passive light-emitting type. In the reflective-type EWOD display technology, the black ink covering the white reflective electrode contracts or extends under the control of voltage, thereby controlling the gray scale so as to implement black-and-white display; or, an additional color filter is involved to cooperate with the black ink so as to implement color display.
However, without the color filter, the reflective-type EWOD display technology in the prior art could only implement black-and-white display, so the display effect is extremely limited. And color display needs additional color filter and thus the structure is complex, thereby limiting further improvement of the reflective-type EWOD display technology.